This command is very helpful when we need to duplicate a test scenario and first we want to find out the installed libraries together with the version and release numbers and architecture. (look example)

Command can be tuned by choosing just the names of libraries we are interested in. For example glibc and gcc.

this will increase the volume by 2 decibels on the pcm channel. the argument to -c is for which sound card to use, the arg after set is the channel (PCM, Master, etc.) and what to set by.

related commands:

amixer -c 0 set PCM 2dB-

decrease volume by 2 decibels

amixer -c 0 set PCM toggle

toggle mute/unmute

this is for alsa systems

for mac os (and maybe other UNIX systems) osascript -e 'set Volume *' where * is any number (can have decimal points) between 0 and 10

This is equivalent to: less `which rcsyslog`

-bash: /bin/grep: Argument list too long

20090119.00011.log:DANGEROUS ERROR

after a terminal gets clobbered (like after you cat a binary file by accident), this is the only way to get it back without re-starting it.

It takes a hunk and shows the different between the three file. Useful when you want to compare two different changed file which from the same base file.

(use emacs ediff3, eyecandy and more useful if you want to merge them from anywhere to anywhere)

The file myfile is owned by tom and has read and write permissions for tom. Group and other permissions are empty which make myfile readable and writable only by tom. setfacl enables user tom to give read permission to user john only. The command 'ls -l' shows a '+' sign telling us that file access control list has been setup for myfile.

works like a charm for the K610i

greps for search word in directory and below (defaults to cd).

-i case insensitive

-n shows line number

-H shows file name

I often need to send screenshots to other people to explain settings and whatever.

So I created this oneline which I use to create the screenshot with imagemagik, upload it via scp to my server and then the command opens an firefox tab with the screenshot.

The screenshot can be a region or a window.

You just have to replace the parts beginning with YOUR.

Good for automating reports that need to run from between two dates.

the -A argument forwards your ssh private keys to the host you're going to. Useful in some scenarios where you have to hop to one server, and then login to another using a private key.

queries local memcached for stats, calculates hit/get ratio and prints it out.

Ran as the postgres user, dumps each database individually. It dumps with the create statements as well, so you can just 'zcat $x-nightly.dmp.gz | psql' to reimport/recreate a database from a backup.

Find files that are older than x days in the working directory and list them. This will recurse all the sub-directories inside the working directory.

By changing the value for -mtime, you can adjust the time and by replacing the ls command with, say, rm, you can remove those files if you wish to.

Note that the file at the given path will have the contents of the (still) deleted file, but it is a new file with a new node number; in other words, this restores the data, but it does not actually "undelete" the old file.

I posted a function declaration encapsulating this functionality to http://www.reddit.com/r/programming/comments/7yx6f/how_to_undelete_any_open_deleted_file_in_linux/c07sqwe (please excuse the crap formatting).